Sargassum/chitin-derived nitrogen-doped activated carbon with exceptional electrochemical performance for supercapacitors

Abstract

Biomass is an ideal precursor for the preparation of electrode materials due to its wide availability, renewability, and cost-effectiveness. Nitrogen-doped activated carbon enhances the electrochemical performance of electrode materials by generating additional pseudocapacitance, thereby broadening the practical applications of supercapacitors. In this study, cross-linked activated carbon was prepared through co-carbonization and KOH activation, utilizing Sargassum and chitin as raw materials. The influence of the Sargassum-to-chitin mixing ratio on the pore structure, morphology, degree of graphitization, and electrochemical properties of the resulting carbon materials was systematically investigated. The resulting Sargassum/chitin-coupled activated carbon exhibited a unique two-dimensional lamellar structure and an exceptionally high specific surface area of 3433.3 m² g⁻¹. The incorporation of nitrogen (N) and oxygen (O) heteroatoms further enhanced the electrochemical performance by generating pseudocapacitance and improving ion transport and wettability. The prepared supercapacitor demonstrated a high specific capacitance of 293 F g⁻¹ at a current density of 0.5 A g⁻¹, along with an excellent capacitance retention of 90.34 % after 10,000 charge/discharge cycles. These results highlight the exceptional electrochemical performance and long-term stability of the developed material.